Synthetic latexes are commonly made by emulsion polymerization. In certain emulsion polymerization processes, monomer compounds are suspended within an aqueous medium as part of micelles that are formed with the assistance of a surfactant. The polymerization reactions in such systems generally proceed by free radical polymerization. When the polymerization is complete, the resulting polymer can be removed from the aqueous medium. Or, in other instances, the resulting dispersion is the end product.
Emulsion polymerization presents a number of advantages as a method of making certain latexes by free radical polymerization. For example, the process allows for rapid polymerization in a temperature-controlled environment. Therefore, the properties of the resulting polymer do not change as the reaction proceeds and heat is generated. Further, emulsion polymerization permits the reaction medium to retain a near-constant viscosity, which also prevents the properties from changing as the reaction proceeds.
One drawback, however, is that the surfactants that enable the polymerization remain in the composition following the reaction. These surfactants can be difficult to remove from the polymer composition. Therefore, it may be desirable to discover surfactant compounds that have a sufficiently low critical micelle concentration and that do not require intensive removal efforts following polymerization.
Thus, there is a continuing need to discover novel surfactants that can serve such purposes and improve the properties of the polymers made by emulsion polymerization.